Pallet loading apparatus



1964 D. POINDEXTER ETAL 3,161,302

PALLET LOADING APPARATUS 4 Sheets-Sheet 2 Filed Nov. 9, 1961 %n ATToRNEg 15, 1964 D. L. POINDEXTE'R ETAL 3,161,302

PALLET LOADING APPARATUS 4 Sheets-Sheet 5 Filed Nov. 9, 1961 D80 1964 D. L. POINDEXTER ETAL 3,161,302

PALLET LOADING APPARATUS Filed Nov. 9, 1961 4 Sheets-Sheet 4 MQ F'ZM 2 r zmzimifim ATTORNEY;

United States Patent ()filice 3,161,362 Patented Dec. 15, 1964 3,161,302 PALLET LOADING APPARATUS David L. ioindexter, Bay St. Louis, Miss., and Robert L. Benched, New Qrleans, and John B. Fos, Jn, Meraux, La, assignors to American Sugar Company, Jersey City, NJ., a corporation of New Jersey Filed Nov. 9, 1961, Ser. No. 151,344 4 Ciaims. (Cl. 214-6) This invention relates to pallet loading mechanism and is concerned more particularly with a novel pallet loader for automatically depositing tiers or layers of non-rigid packages, such as bags, upon a pallet with the packages in a tier in close contact and the tops of the packages lying approximately in a plane.

Automatic loaders for depositing tiers of packages, such are cartons, upon pallets are now commercially available and, in one such machine, the cartons delivered to the loader are placed upon a stripper disposed above a support, on which an empty pallet has been placed. The cartons are placed upon the stripper in the general arrangement which they are to have in a tier on the pallet and, when the stripper has received the cartons required for a tier, the stripper is moved in a horizontal plane beneath an abutment at one side of the support. As the stripper is so moved, the cartons are held back by the abutment and the group of cartons is also compressed from the sides, so that the cartons are forced into close contact. Continued movement of the stripper, while the cartons are held by the abutment, causes the stripper to move from beneath the cartons and they drop upon the pallet. The support for the pallet is then lowered a step, the stripper is moved back over the support, and the operations are repeated, until the pallet is fully loaded.

In the use of the automatic loader described for loading pallets with large non-rigid packages, such as paper bags holding 100 lbs. of loose sugar, difiiculties have been encountered in transferring the bags from the stripper to the pallet and, at the same time, maintaining the bags in contact and with their top surfaces approximately in a plane. The reason is that, as the stripper is moved from beneath a group of bags and the bag or bags near the trailing edge of the stripper start to drop off, these bags have a tendency to slide laterally relative to the support with the result that they may come to rest partly oii the support out of contact with adjacent bags and with their upper surfaces at an angle to the horizontal. Such bags are unstable and, if other bags are deposited upon them, an unstable load is produced, which may lose bags or may cause the pallet to be turned over while it is being stored.

The present invention is, accordingly, directed to the provision of automatic loader for depositing nonrigid packages, such as bags, upon pallets to form tiers, which are properly centered upon the pallets and in which the bags lie in close contact and with their upper surfaces substantially in a plane. In the new loader, the bags are placed in the desired tier arrangement upon a main stripper and are moved into close contact just before the main stripper starts "to move beneath an abutment. As the movement of the main stripper continues, so that it passes from beneath the tier of bags held back by the abutment, the edges of the bags remote from the abutment and dropping off the trailing end of the stripper are supported by an auxiliary stripper, which has been moved into place above the support. The auxiliary stripper prevents sidewise movement of the bags first released from the main stripper and it remains in position, until the main stripper is about to move wholly from beneath the tier. At that point, the auxiliary stripper moves away from the main stripper and the tier drops upon the pallet on the support. A tier so deposited is properly oriented and the bags in the tier are in close contact and have upper surfaces lying substantially in a plane. The tier is stable and it provides a 1suitable support for overlying tiers and insures a stable oad.

For a better understanding of the invention, reference may be made to the accompanying drawings, in which FIG. 1 is a plan view of apparatus embodying the invention for loading bags upon pallets;

FIG. 2 is a partial plan view of the apparatus on FIG. 1 on an enlarged scale and with parts broken away.

FIGS. 3 and 4 are sectional views on the lines 3-3 and 4-4, respectively, of FIG. 2;

FIGS. 5A, 5B, and 5C are diagrammatic vertical sectional views showing the apparatus at different stages in its operation;

FIG. 6 is a diagrammatic plan view showing two different arrangements of four bags forming a single tier; and

FIG. 7 is a plan view of two difierent arrangements of three bags forming a single tier.

The pallet loading apparatus shown in the drawings comprises a conveyor 1t), to which the bags are delivered by any suitable means, such as a gravity conveyor 11. The conveyor 19 is formed of a row of parallel rollers 12 mounted in side frame members 13 and having shafts carrying gears 12a driven by a motor 14 through a chain 15. A plurality of stop plates 16, 17, and 18 are mounted between respective pairs of the rollers 12 and may be automatically raised to form stops in different positions for bags being advanced by the rollers.

At one side of the conveyor 16 is a housing 19 containing a ram 20 mounted for movement across the conveyor parallel to the roller axes. The ram is provided with a rack 21, by which it may be advanced over the conveyor and returned into the housing by a pinion 22 meshing with the rack and driven by a motor 23.

A main s'tripmr 24 is mounted at the side of the conveyor 10 opposite the housing 19. The main stripper is formed of a row of parallel rollers 25 with their axes at right angles to the axes of the rollers 12 and side frame members 26, 27, in which the rollers are mounted. The stripper is mounted for movement in its plane toward and away from the conveyor 10 on a pair of rails, of which only the rail 28 (FIG. 3) is shown. The frame member 26 carries a rack 29 on its under surface and the stripper is moved by a pinion 3t? meshing with the rack and driven by a motor 31.

As thebags are advanced by the conveyor 1! the first bag B1 of the group to form a tier intercepts the beams issuing from sources 32, 33 and normally falling on photocells 34, 35, respectively. These photocells are in circuit with a control mechanism, which determines the arrangement of the bags in a tier and controls the action of a pusher 36 and an interceptor arm 37. The pusher comprises a hydraulic cylinder 38, the piston rod 39 of which carries an enlarged head 40 and, when the pusher is actuated, the head 49 strikes a bag on the conveyor 19 near the rear end of the bag and swings it to the position of the bag B4 (-FIG. 2). At the same time, the arm 37 is moved in over the conveyor to engage the adjacent for the purpose. When the next bag B2 is advanced, the

control mechanism does not actuatethepus-her 3 6- and-- the arm 37 so that the bag moves end on until it comes to rest against the stop plate 17, which has been raised.

As soon as the bag B2 has-engaged the stop plate, the

ram-20 is moved forward by its motor 23 and pushes the bags upon the stripper, Where, they travel on the rollers.

The nextbag B3 is.

16, which has been raised. As soon as the bags B3 and B4 are in place, theram moves the bagsoii the conveyor and uponthe stripper to complete, the tier, as shown in FIG. A. V

A support 43 for a pallet P is disposed. beneath the main stripper in its initial. position adjacent theconveyor and the support can. be raised and lowered by suitable means conventionally illustrated as a screw 44. The lowering of the support 43is controlledby a switch S1 which is operated bya flap 45. mounted on a shaft-46 above the main stripper and normallyextending down from theshaft. As the bags are pushed on the main. stripper by the ram, the flap is swung to operate the.v switch and. the support is moved down one step to receive a tier of bags.

A closer plate 47 is mounted on the. piston rods of a pair of hydraulic cylinders .48, 49 to overlie the main stripper along one side and .a. fixed. stop plate 50 is mounted on arms. 51, 52 to overlie the main stripper. along. its, oposite side. As. soonv as thebags to form a tier have; been loaded onth main stripper, thecylinders 48, 49. are actuated to move the closer plate inwardly and push the bags into. close contact and against the stop plate 50. The. motor 31 is then started to move the main stripper away from the conveyor 10. During suchmover stripper moves with it to the position shown in FIG. 5B,

inwhich the plate 54 overlies the edgeofthe pallet P- adjacent to the conveyor 10. When the auxiliary stripper is in this position and the movement of the main stripper permits the edges of the bags- B3 and B4 to drop down as previously explained, these edges of the bags land upon the top of the plate 54 with the result that the bags assume a slightly inclined position With'their outer edges higher than their inner edges. The inclination. of the bags is such that there is substantially no tendcncy for them to slide laterally.

The movement of the auxiliary stripper is initiated by the closing of a switch S2 by the main stripper in its outward movement and, when the main stripper approaches the end of its outward travel, it operatesfa switch S3,-

which causes the cylinder 65; to. straighten the toggle and cause the auxiliary stripper to move. out from'under the bags resting upon it. The bags then drop into. their de-,

I in the lowermost. position, the pallet isremoved from the support by conventional conveyor means, an empty pallet isjplaced upon the support, and the support is raised to receive the first tier of another load.

' Thearrangementof thebagson the pallet may be as shown-in. FIGS. 6 arid 7.: FIG. 6 illustratestwo diiferent ment of the main. stripper, the closerplate remains in place to hold thebags of the tier in contact.

As the main stripper passes beneath the the bags on the stripper are held back and the bags at the trailing end of the stripper, namely, bags. B3 and B4,

abutment 41, l

are first released to dropupon the palletR. or atierof. 7

bags previously loaded-upon. the pallet.

jacent the conveyor 10;first drop down, so that the bags are momentarily .in -an inclined position and have a tendency to slide laterally relative tothe pallet. Suchmovemer t of the bags would separate them from thebagsBl and B2 and the top of. the tier would be uneven. and the pallet load would;beunstable. In order to prevent the an auxiliary stripper. The auxiliarystripper comprises a carriage 53 formed ofrfan' anglebar 54 and side; plates 55 having rollers runshaft 59carries a second pinion 60 in mesh with the rack 61 movable endwise through a guide 62 loosely mounted on the shaft 59. At one end, therack- 61 is pivotallycQnnected to an arm 63 mounted to swing on. a fixed pivot As the, main: 7 stripper moves from beneath-these bags, their edges ad-.

. lateral movement of thebags, the loader is equipped, with e tiers, eachcont aining; four bag s B1.B4,. which. arefa'rranged to form. a hollowsquare. In each arrangement, two of the bagshave been placedupon the stripper without first having been turned'through 90 while the. re-

maininggtwo have' been so. turned. In FIG. 7, there are shown two diflerent tiers. of three bags. each and, in one tier, two bags have been turned and one left unturned, while, in the other, the reversearrangement is used. Re-

gardless. of the; form of tier employed, the auxiliary stripper functions to prevent lateral displacement of the I bags .st'freed from the main stripper and insures: thatmovable in thediliection of movement of the main stripper to and froma position beneath the'edge of a tier of pack-.

' 5 ages being removed from themain stripper by the abut- 64 and the rack and the arm form a toggle which can be I straightened and collapsed by a hydraulic cylinder 65 mounted for swinging movementon a pivot 66 and hav-f ing its piston rod connected to the. arm 63 by: a slot and pin connection. Whenthe, pistonjof the cylinder is v moved in one direction, the rack 61-is moved to rotate The operation of the main and auxiliary, strippers is il lustrated in FIGS. 5B and 5C. Whentheimainstripper.-

. tar s. ib y r m he o yp 0. t e ilia y V for rotating the shaft lin'oppositedirections.

ment,-means for moving ,the. auxiliary. stripper, means actuated: by the-.rnain stripper as it; moves away from its position above-thesupport-to cause a limited movement of the auxiliary stripper inthe same direction as the main stripper and means. actuatedby the main, stripper as it approaches the end of its movement awayirom its posi tion above the support to. cause. the=auxiliarystripper to. move in a. direction opposite to thedirectionof movement of. the main stripper.

2. The1pa1letloading mechanism of claim- 1 in which.

the. auxiliary stripper .is provided with a. rack mounted to extend parallel tothe directionlo'f movement of the auxiliary stripper and the means for moving the auxiliary stripper. include. a pinion engaging the rack, a shaft carrying the pinion, and'means including a hydraulic cylinder 3. The pallet loading mechanism of claim 1, in

7 which. e ux i ..s ri per. sl slcaaj nias f. ut bs.

width of the main carriage and having rollers at its sides, and a track supports the rollers for movement of the carnage.

4. The pallet loading mechanism of claim 1, in which the auxiliary stripper includes a plate adapted to arrest the downward movement of the edges of the packages first freed from the main stripper by its movement beneath the abutment from above the support.

References Cited by the Examiner UNITED STATES PATENTS May 74-110 Raynor 19821 Fenton 198-33 Forey 74-110 McGrath 198-6 

1. A PALLET LOADING MECHANISM WHICH COMPRISES A SUPPORT FOR A PALLET, AN ABUTMENT AT ONE SIDE OF THE SUPPORT, A MAIN STRIPPER FOR RECEIVING A TIER OF NON-RIGID PACKAGES, MEANS FOR MOVING THE MAIN STRIPPER BENEATH THE ABUTMENT IN A HORIZONTAL PLANE FROM AND TO A POSITION ABOVE THE SUPPORT, THE ABUTMENT REMOVING THE TIER OF PACKAGES FROM THE STRIPPER AS THE STRIPPER MOVES BENEATH THE ABUTMENT FROM ABOVE THE SUPPORT, AN AUXILIARY STRIPPER DISPOSED AT THE SIDE OF THE SUPPORT REMOTE FROM THE ABUTMENT AND MOVABLE IN THE DIRECTION OF MOVEMENT OF THE MAIN STRIPPER TO AND FROM A POSITION BENEATH THE EDGE OF A TIER OF PACKAGES BEING REMOVED FROM THE MAIN STRIPPER BY THE ABUTMENT, MEANS FOR MOVING THE AUXILIARY STRIPPER, MEANS ACTUATED BY THE MAIN STRIPPER AS IT MOVES AWAY FROM ITS POSITION ABOVE THE SUPPORT TO CAUSE A LIMITED MOVEMENT OF THE AUXILIARY STRIPPER IN THE SAME DIRECTION AS THE MAIN STRIPPER AND MEANS ACTUATED BY THE MAIN STRIPPER AS IT APPROACHES THE END OF ITS MOVEMENT AWAY FROM ITS POSITION ABOVE THE SUPPORT TO CAUSE THE AUXILIARY STRIPPER TO MOVE IN A DIRECTION OPPOSITE TO THE DIRECTION OF MOVEMENT OF THE MAIN STRIPPER. 